TPS question or two

[flower_king001]

Have owned my 1998 EV for the past 10 years. I never changed out the TPS but been having drive-ability problems for the past few months. I seem to hit a spot around 78-80 MPH where the bikes misses. My questions is as I have gone through a slew of things that I'll list later. Question, bike has a Harley Davidson 27271-95 HD TPS in it. It was set on 2.1 and smooth all the way to and from WOT. So I took it out and sprayed some CRC and turn it back and forth with a flat head screwdriver and set it back to 2.1. Same drive-ability problem trying to maintain a steady 78-80 mph. So the TPS seems good by the readings, could it still be bad?

Thanks

[RinkRat II]

     KoF,  The Harley TPS and The Guzzi TPS are similar but not quite the same ,as their performance curves are different electrically due to fueling,spark advance differences between a Harley and your Guzzi.  As to your question, they can get worn spots in them as they are just a potentiometer. One thing you could try is to leave the tps just loose enough to move it with finger pressure and go for a ride. When it stumbles move it ever so slightly and see if it clears. If so it'll be pretty obvious and you'll need to replace it.  Hope this helps.

        Paul B

[fotoguzzi]

How old are your plug caps and wires? Can you replicate at same rpm in say 4th gear?

[pehayes]

How did you get electronic cleaner INSIDE?  I drilled a 1/16" hole here where the white dot is located.  Plugged with silicone when finished.



Patrick Hayes
Fremont CA

[pehayes]

What are you using to set the base TPS value?  I would recommend a voltmeter to obtain 150mV base install with linkages disconnected and throttle butterfly fully closed.  Once the linkage is reconnected you should have around 385mV.

Patrick Hayes
Fremont CA

[flower_king001]

I'm using Technoresearch Centurion

What are you using to set the base TPS value?  I would recommend a voltmeter to obtain 150mV base install with linkages disconnected and throttle butterfly fully closed.  Once the linkage is reconnected you should have around 385mV.

Patrick Hayes
Fremont CA

[flower_king001]

If I had a worn spot I would think it would show up while viewing the Centurion software. The TPS doesn't stick at all and readings from 2.1 all the way to WOT and back are as smooth as can be with no jump in numbers. I did think about setti ngthe TPS from 2.1 to 2.3 and see if that makes a difference.

     KoF,  The Harley TPS and The Guzzi TPS are similar but not quite the same ,as their performance curves are different electrically due to fueling,spark advance differences between a Harley and your Guzzi.  As to your question, they can get worn spots in them as they are just a potentiometer. One thing you could try is to leave the tps just loose enough to move it with finger pressure and go for a ride. When it stumbles move it ever so slightly and see if it clears. If so it'll be pretty obvious and you'll need to replace it.  Hope this helps.

        Paul B

[flower_king001]

wires and caps about 2 months old. Purchased them through MGCycle..NGK 5K ohm caps, 7 mm wire

Replicate in 4th gear? Have not tried that yet. My only other thought is to pull the injectors and send them off to be cleaned.

How old are your plug caps and wires? Can you replicate at same rpm in say 4th gear?

[John Croucher]

How did you get electronic cleaner INSIDE?  I drilled a 1/16" hole here where the white dot is located.  Plugged with silicone when finished.



Patrick Hayes
Fremont CA

A TPS will come apart very easily.  There is not anything complicated inside.  A three pronged brass brush rubbing against a internal wire winding.  The brass brush section on one I replaced was bent, worn, and not touching the wire coil correctly.  Actually touching advanced and retarded.  I tossed it and installed a new one.  Bike ran much better.

Setting does not have to be complicated.  Set you idle speed and adjust the TPS to 500 mva.  Takes about 2 minutes. No need to turn, adjust, check, adjust, close throttle, open throttle, synchronize, turn, check.   

 If you put a timing light on the bike and check the timing mark while adjusting the TPS, you will see the engine timing change.

Grab the sparkplug wires and caps while the engine is running and on hand on a good ground on the bike.  If you get shocked, replace wires, caps and or coils.   

[flower_king001]

I didn't drill a hole...the TPS was not all that dirty on the outside/inside where I could see. Just sprayed CRC and turned with screwdriver. All felt very smooth

While viewing software/program on my laptop and turning throttle if all is smooth going going up and down the number scale, would you think I did to drill a hole and clean or? Could there still be a problem if I see nothing in the readings on the program?

How did you get electronic cleaner INSIDE?  I drilled a 1/16" hole here where the white dot is located.  Plugged with silicone when finished.



Patrick Hayes
Fremont CA

[guzzisteve]

You could try adjusting the sensor to a different spot. The book has a + or - on the setting. I have noticed the motors I work on like +15mv better than the 150 number. I've had very good results doing this. It helps w/motors running open intake or exhaust.

I have also seen a post here giving location of the original TPS for a reasonable price. I have had no runability issues w/HD sensor.

Just had a thought, have you checked the fuel pressure, unless the pump is newer than 20yrs old.

[Chuck in Indiana]

If I had a worn spot I would think it would show up while viewing the Centurion software. The TPS doesn't stick at all and readings from 2.1 all the way to WOT and back are as smooth as can be with no jump in numbers. I did think about setti ngthe TPS from 2.1 to 2.3 and see if that makes a difference.

Back in the day, I had a bad TPS on the Jack-All, and the Centurion software didn't show it. You'll have better luck checking it with an ohm meter, preferably analog.

[malik]

Found out how to test the TPS with Guzzidiag on the V7C - watched the Throttle V while slowly moving the revs up the range. At 3,400rpm the V would fluctuate wildly between 6 & 10.8, while at other revs the V was fairly steady. Replacing the TPS cured the missing at around 3,500-4,000rpm on constant throttle. Success at last.

[flower_king001]

Thanks for that Patrick..I did just that today and reset. I also had a new temp sensor so I installed that as well even-though it was checking good with Centurion. I will test bike on my way to work this afternoon.

 Prior to the above..the bike starts and idles just fine and after a few miles of warming engine up I don't have the hesitation problem. Thoughts?

How did you get electronic cleaner INSIDE?  I drilled a 1/16" hole here where the white dot is located.  Plugged with silicone when finished.



Patrick Hayes
Fremont CA

[flower_king001]

Grab the sparkplug wires and caps while the engine is running and on hand on a good ground on the bike.  If you get shocked, replace wires, caps and or coils.

Did just as you stated yesterday and all was good.

[flower_king001]

Just had a thought, have you checked the fuel pressure, unless the pump is newer than 20yrs old.

No...but just added it to my lists of things to do...thanks!

[ejs]

Thanks for that Patrick..I did just that today and reset. I also had a new temp sensor so I installed that as well even-though it was checking good with Centurion. I will test bike on my way to work this afternoon.

 Prior to the above..the bike starts and idles just fine and after a few miles of warming engine up I don't have the hesitation problem. Thoughts?
[/qudote]
To much air when cold

[flower_king001]

Update:

 Replaced TPS the other day and bike runs brilliant! Purchased the TPS here:

https://ca-cycleworks.com/pf3c

thanks to all here1

[RinkRat II]

  Flower_King, glad you got it sorted!

     Paul B

[Ncdan]

That's a fare price unlike the TPS on the 1400, 400-450.00. Rip-off!